Google Updated Professional-Cloud-Security-Engineer Exam Questions and Answers by brian

To provide on-premises hosts with access to Google APIs without using public IP addresses or the public internet, Google Cloud provides Private Google Access for on-premises hosts. This feature allows traffic to stay within the Google network via Cloud Interconnect or Cloud VPN.

According to the official Google Cloud Documentation (Configuring Private Google Access for on-premises hosts):

"Private Google Access for on-premises hosts provides a way for on-premises systems to connect to Google APIs and services by routing traffic through a Cloud VPN tunnel or Cloud Interconnect attachment (VLAN). On-premises hosts don't need public IP addresses; instead, they use internal IP addresses."

Key Implementation Steps:

Network Connectivity: Ensure your on-premises network is connected to your VPC via Cloud Interconnect or VPN.

DNS Configuration: You must configure your on-premises DNS to map API requests (like storage.googleapis.com) to special IP ranges. There are two primary options:

private.googleapis.com: Resolves to 199.36.153.8/30. This range supports most Google APIs but only those that are VPC-Service Control compatible.

restricted.googleapis.com: Resolves to 199.36.153.4/30. This is required specifically when using VPC Service Controls (VPC-SC) to ensure data cannot be exfiltrated to services outside the perimeter.

Routing: You must configure custom static routes in your VPC or use BGP to advertise the 199.36.153.8/30 (or 199.36.153.4/30) range back to your on-premises router.

Why other options are incorrect:

A is incorrect: Shared VPC is used to share a network across multiple Google Cloud projects, not to extend a VPC directly to on-premises hardware.

C is incorrect: While the IP range 199.36.153.8/30 is correct for private.googleapis.com, Cloud NAT is used for outbound internet access from VPC instances without external IPs; it does not facilitate private on-premises-to-API connectivity.

D is incorrect: VPC Peering connects two VPCs within Google Cloud. You cannot "peer" an on-premises data center directly via VPC Peering; you must use Interconnect or VPN.

To share a service (like an AI model) across project boundaries privately and securely—without complex VPC peering or exposing it to the internet—Private Service Connect (PSC) is the recommended solution.14

According to Google Cloud Documentation (Private Service Connect for Vertex AI/Custom Services):

"Private Service Connect allows a service producer to expose a service (via an Internal Load Balancer) to service consumers in other VPC networks or projects.15 The producer creates a Service Attachment that points to the load balancer.16 The consumer creates a PSC Endpoint in their own VPC. Traffic stays entirely within the Google backbone, and the producer can maintain an 'Allowlist' of Project IDs that are permitted to connect."

Why this fits the requirements:

Isolation: The model remains in its own project and is not reachable via the internet (Option C is out).

Granular Control: PSC allows you to explicitly list which Project IDs can access the service attachment (Option A).17

Scalability: It avoids the "transitive peering" and "IP overlap" limitations often found in Shared VPC or Peering architectures (Option B).

Uniform Bucket-Level Access: Enable uniform bucket-level access for all your Cloud Storage buckets. This feature ensures that access control is applied consistently at the bucket level, simplifying management and improving security.

Domain Restricted Sharing: Enforce domain-restricted sharing through an organization policy. This policy ensures that only users within your organization’s domain can access the data in the buckets, preventing public exposure.

Policy Enforcement: Apply the necessary IAM policies and ensure that no buckets are configured to allow public access. This combination of settings ensures that data in Cloud Storage buckets remains private and accessible only to authorized users within your organization. References:

Google Cloud - Uniform Bucket-Level Access

Google Cloud - Organization Policy Service

The problem states that Google Cloud applications need to access external web services and requires the ability to monitor, control, and log this access.

Monitoring, Controlling, and Logging external web access: This specifically points to a proxy solution, which can intercept, inspect, and log HTTP/S traffic.

Secure Web Proxy (SWP): Google Cloud's Secure Web Proxy is designed for exactly this use case. It acts as an explicit forward proxy for HTTP(S) traffic, allowing organizations to implement granular access controls, inspect traffic for security threats, and log all outbound web requests from their Google Cloud environment.Extract Reference: "Secure Web Proxy is a managed service that lets you deploy and manage an explicit forward proxy to protect your organization's internal resources from web-based threats and to control access to external web applications." and "With Secure Web Proxy, you can: Enforce granular access policies based on different attributes, Log all HTTP(S) requests that are handled by the proxy, and Monitor web traffic for threats." (Google Cloud documentation: https://cloud.google.com/secure-web-proxy)

Let's evaluate the other options:

A. Configure VPC firewall rules to allow the services to access the IP addresses of required external web services: VPC firewall rules operate at Layer 4 (TCP/UDP) and Layer 3 (IP). While they can allow or deny traffic to specific IP addresses and ports, they cannot monitor, control, or log HTTP/S requests at the application layer. They don't provide granular control over which web services are accessed or inspect the content of the requests.

C. Configure Google Cloud Armor to monitor and protect your applications by checking incoming traffic patterns for attack patterns: Google Cloud Armor is primarily a Distributed Denial of Service (DDoS) protection and Web Application Firewall (WAF) service. It focuses on protecting applications from incoming threats (ingress traffic), not controlling and logging outgoing access to external web services.

D. Set up a Cloud NAT instance to allow egress traffic from your VPC: Cloud NAT allows instances without external IP addresses to connect to the internet. While it enables egress, it does not provide monitoring, control, or logging capabilities for specific web services at the application layer. It's a network address translation service, not an application-layer proxy.

Therefore, setting up a Secure Web Proxy is the most appropriate solution to meet the requirements of monitoring, controlling, and logging access to external web services from Google Cloud applications.